Abstract

In this study, we report the effects of thermal annealing in nitrogen ambient on the
optical and electrical properties of zinc oxide (ZnO) nanorod (NR) arrays for the
application in light emission diodes (LED). The single-crystalline ZnO NR array was
synthesized on p+-Si (111) substrate without seed layer using simple, low-cost, and low-temperature
hydrothermal method. The substrate surface was functionalized by hydrofluoric acid
and self-assembled monolayer of octadecyltrimethoxysilane ((CH3 (CH2)17Si(OCH3)3). ZnO NRs were characterized by field emission scanning electron microscopy (FESEM),
X-ray diffraction (XRD), and micro-photoluminescence (micro-PL). The results of FESEM
and XRD indicate that single crystalline ZnO NRs with (002) preferred orientation
along the substrate surface is successfully grown on functionalized p+-Si (111) substrate. The current–voltage and electroluminescence (EL) characteristics
of the LED show that the most suitable annealing temperature ranges from 400°C to
600°C. Both PL and EL spectra show broadband emissions, ultraviolet and visible (green-yellow)
light. The white-like light emission is able to be observed by naked eyes.